see #223

Anonymous mmap() calls have no backing file and therefore won't match
any Darshan characterization records, so we can skip the record lookup
in this case.  This also fixes a deadlock on Cray systems with hugepages
enabled, see #210.

Signed-off-by: Cong Xu <cong.xu@intel.com>

1. Use Lustre Module in Darshan
2. Integrate DXLT IO tracing code into one module
3. Add hooks in POSIX and MPI Modules
4. Add Intel copyright
Signed-off-by: Cong Xu <cong.xu@intel.com>

1. Use Lustre Module in Darshan
2. Integrate DXLT IO tracing code into one module
3. Add hooks in POSIX and MPI Modules
4. Add Intel copyright
Signed-off-by: Cong Xu <cong.xu@intel.com>

POSIX_F_OPEN_TIMESTAMP is now POSIX_F_OPEN_START_TIMESTAMP
POSIX_F_CLOSE_TIMESTAMP is now POSIX_F_CLOSE_END_TIMESTAMP

I also added POSIX_F_OPEN_END_TIMESTAMP and
POSIX_F_CLOSE_START_TIMESTAMP, so we can better understand how
long open and close phases are for some applications.

This function can be called by modules to allow FS-specific
modules to gather data for a given file path/file descriptor.
Currently integrated into POSIX and STDIO modules.

There are cases where lustre stripe info is not available the
first time a given file is opened (e.g., when using the
llapi_file_create call). So, now we call into the lustre module
every time a file is opened to give the module a chance to gather
data.

A common record comparision/sort routine is now defined in
darshan-common which can be used by any modules with fixed-length
records and whose records first field is the darshan_base_record.
The comparison was also updated to sort secondarily by darshan
record identifier to resolve a potential bug in the way we have
traditionally sorted the records.

This interface provides some convenience functions for mapping
opaque record identifiers (could be a filename, file descriptor,
or any other type of file handle) to a corresponding runtime
structure referencing the actual file record. This runtime
structure should at least contain a pointer to the actual file
record, and can also persist arbitrary state for this record.

- memory management is now entirely handled by darshan-core for
  module records
    * when registering new records, darshan-core returns the
      corresponding buffer to write it to, rather than allowing
      module to determine this
- modules now decide whether darshan-core should track record
  names by passing either a valid name or NULL to the register
  function
    * this allows modules to register records that aren't really
      tracked by darshan-core
- only the POSIX module has been ported to new changes for this
  commit

- read and write start timestamps should record start timestamp of first
  read/write to *begin*, not start timestamp of first read/write to
  complete
- mirrors earlier fix to open timestamps

- be careful to record start timestamp of first open to start rather
  than start timestamp of first open to complete

- move fopen/fopen64 wrappers to stdio module
- make infrastructure for tracking stream pointers based on similar fd
  infrastructure in posix
- define placeholder record structs
- wrappers don't actually do anything yet

the POSIX module will call into the Lustre module for each file
record created that corresponds to a file from a Lustre FS. No
counters are currently stored but most of the module strucutre
has been stubbed.